State and Transition Model (STM) Application and Use

STMs are an important tool for adaptive management and can help set realistic management objectives by identifying the range of potential states for an ecological site. They also can serve as the basis for rangeland inventory, assessment, and monitoring by providing a framework to understand vegetation dynamics and identify appropriate monitoring indicators. STMs also suggest potential management strategies and can be used to develop and test management hypotheses about the effectiveness of different practices on ecological sites and states. The Bureau of Land Management (BLM) uses STMs to help manage many of its responsibilities, such as the following:

Fire Management — Different states in the same ecological site may react differently to fire. Prescribed burns may have different outcomes (in terms of erosion and plant re-growth, for example) depending on the current state. The STM describes the role of fire in vegetation dynamics, suggests which ecological sites and states are more vulnerable to wildfire, describes which can be managed with prescribed fire, and provides information about how to manage to reduce wildfire risk.

Grazing Management — STMs describe the potential of different types of land to support livestock grazing, and illustrate how grazing affects plant composition on an ecological site as well as how grazing can help make desired changes or avoid negative outcomes.

Hydrology — Upland vegetation and site characteristics can impact infiltration and runoff rates as well as resulting water quality and sediment loads. STMs provide information about erosion potential that could have a cumulative impact on watershed dynamics.

Invasive Species — Human and natural disturbances can lead to areas that are more vulnerable to invasive species and STMs can show the ecological sites and states to prevent their spread.

Recreation — Different states provide assorted recreational opportunities and may be preferred by some user groups. Using an STM to understand the site potential may influence recreation management and planning and can predict the impacts of recreation on plant communities and site stability.

Restoration — STMs help prioritize restoration according to expected success, by understanding how states will change, the plant communities that can be supported by the site, and by providing useful information for selecting plants for re-vegetation.

Wildlife — Ecological sites and states display different habitats and/or quality for assorted wildlife species, enabling the prioritization of areas for conservation and improvement projects.

Woodland Management — Beyond grassland and shrubland systems, Ecological Site Descriptions (ESDs) are for woodlands, and can help to plan for sustainable woodland management, manage pest outbreaks and understand vegetation change.